1. Field of Invention
The present invention relates generally to the field of packaging equipment and more particularly to apparatus for adjustably positioning a carton blank in a correct position for folding and sealing prior to filling.
2. Description of the Related Art
Packaging machines of the form-fill-seal type generally involve the formation of a carton, filling the carton with a product, and thereafter sealing the carton. Typically, the carton is formed by mounting a carton blank, comprising a paperboard rectangular tube, for example, upon a mandrel, where the bottom of the blank is folded and sealed against a pressure pad. The open-top carton is then removed from the mandrel for filling and then sealing. When the product is a food product, such as juice or milk, the interior of the carton is often maintained aseptic. At the end of a production shift, or at the end of a given production run, or in other instances, it becomes necessary that the portion of the machine that is exposed directly to the product, particularly within a filling station of the machine, be cleaned and/or sterilized. The cleaning operation generally involves flushing clean water over and/or through the components within the packaging machine, followed by drying, in some instances, and sterilization of the cleaned equipment by exposure to a sterilant such as hydrogen peroxide.
Desirably, this cleaning and/or sterilization is accomplished without the disassembly or removal of one or more of the components of the equipment. Following cleaning of the components, the cleaned and/or sterilized equipment is preferably sealed until the machine is again placed into production. Toward these ends, it is common to encase the equipment of a packaging machine within a clean-in-place enclosure, which in most instances comprises a housing capable of being made fluid-tight, and within which the cleaned/sterilized equipment is housed. During operation, portions of this housing are open for the movement of carton blanks into and sealed cartons out of the enclosure, hence through the formation and filling stations. These openings through which the carton blanks and cartons pass are provided with removable covers which, when in place, render the entire housing fluid-tight.
When a carton blank is mounted upon a mandrel for formation, the exact position is important to ensure that the fold lines are properly positioned relative to the pressure pad for closing and sealing the bottom of the carton. Accordingly, a stop mechanism is provided on each mandrel to stop the blank, as it slides over the mandrel, in the correct position, relative to the pressure pad, for closing and sealing.
Packaging equipment is often used to form, fill and seal several different sizes of cartons. For example, a single packaging system may be used to produce both pint and quart size packages. These cartons may have the same cross-section and differ only in height, so that there is no need to replace mandrels or pressure pads for differently sized cartons. However, each differently sized carton requires that the stop mechanism be located at a different position on the mandrel. Accordingly, adjustable stop mechanisms have been provided. In one prior apparatus, the carton stop is adjusted by slidingly mounting the stop mechanism on a post adjacent to the mandrel. The post includes a plurality of spaced-apart grooves. The stop mechanism includes a detent, which may be threaded or spring-loaded, for example, to provide secure engagement with a groove located at the correct position to place the stop mechanism properly for a particular size of carton blank.
Although useful for allowing adjustment for different sizes of cartons, the prior stop mechanism requires manual adjustment. As discussed hereinabove, in many packaging environments, particularly where food is being packaged, the equipment is enclosed during a production run. Accordingly, manual adjustment of the stop mechanism invades the environment and requires a substantial period of time to clean the equipment and re-establish the operating environment. Moreover, the manually operated stop mechanism is adjustable only to very specific, pre-defined positions. It is not adaptable to small adjustments as may be required by slight variations in carton blank size.
In accordance with one aspect of the present invention, there is provided a novel stop mechanism which is continuously adjustable along the length of a mandrel to accommodate varying sizes of cartons and which is selectively adjustable within an enclosure.